%0 Journal Article
%T A Rapid Extractive Spectrophotometric Method for the Determination of Tin with 6-Chloro-3-hydroxy-2-(2∩-thienyl)-4-oxo-4H-1-benzopyran
%A Ramesh Kataria
%A Harish Kumar Sharma
%J Advances in Chemistry
%D 2014
%R 10.1155/2014/750973
%X An extractive spectrophotometric method for the determination of the trace amounts of tin has been carried out by employing 6-chloro-3-hydroxy-2-(2∩-thienyl)-4-oxo-4H-1-benzopyran (in acetone) (CHTB) for the complexation of the metal ion in HCl medium. The colored species thus produced is quantitatively extracted into dichloromethane and shows the maximum absorbance at 432每437ˋnm. The method obeys Beer＊s law in the range 0.0每1.3ˋ米gˋmLˋ1 of tin with molar absorptivity and Sandell＊s sensitivity of ˋLˋmolˋ1ˋcmˋ1 and 0.0020ˋ米gˋSnˋcmˋ2, respectively, at 435ˋnm. The method is highly selective and free from the interference of a large number of elements including platinum metals. The ratio of metal to ligand in the extracted species is 1ˋ:ˋ2. Utilizing this method, the analysis of various synthetic and technical samples including gun metal and tin can have been carried out satisfactorily. 1. Introduction Tin does not occur free in nature and is found almost exclusively as tin oxide known as cassiterite or tin stone. Tin although a toxic metal, still it is being widely employed in manufacturing important alloys [1] and as solders for the joining of electronic components. The excess use of tin in daily life as fungicides in crops, in food packaging, and as stabilizer for polyvinyl chloride may introduce the inorganic tin {Sn(II) and Sn(IV)} in the environment. Out of these two, Sn(II) seems to be more toxic as compared to Sn(IV) [2]. In the literature, there are numerous analytical methods for the measurement of tin which are based on sophisticated instruments [3每10]. These methods are highly sensitive but generally tedious and prone to serious interferences from other elements. In contrast spectrophotometric methods are preferred due to their simplicity and speed in routine analysis. The reported studies have shown that a large number of reagents such as methyl orange [11], benzopyran derivatives [1, 12, 13], 2-(5-nitro-2-pyrilazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino-phenoyl] [14], pyrocatechol violet [15每18], phenylfluorone [19, 20], dibromohydroxyphenylfluorone [21], arsenazo-M [22], isoamyl xanthate [23], diacetyl-monoxime-p-hydroxybenzoyl-hydrazine [24], bromopyrogallol red [25], potassium ethylxanthate [26], ferron [27], and 5,7-dichloro-8-quinolinol [28] have been used for the spectrophotometric determination of tin(II,IV) content. Among these many reagents [18, 21, 23, 26每28] are nonselective as they suffer from the interference, have low sensitivity [11, 12, 23, 24, 26每28], and some of them are time consuming, as they require time for full color
%U http://www.hindawi.com/journals/ac/2014/750973/